Transition input width - html

Question

I have the input search field. When I click on it I need it to become wider performing smooth transition from right to left, i.e. the input is located on the right side of the page and when I click on it it should stretch to the left in some number of pixels and become wider.
Here's my css:
#header #search input {
background: #FFF;
padding: 1px 1px 1px 5px;
width: 178px;
height: 21px;
border: 1px solid #CCCCCC;
border-radius: 6px;
-webkit-transition: all .5s;
-moz-transition: all .5s;
transition: all .5s;
}
#header #search input:focus {
background: #FFF;
padding: 1px 1px 1px 5px;
width: 300px;
height: 21px;
border: 1px solid #CCCCCC;
Could you help me with implementing that?

Answer 1

input[type="search"] {
background: #FFF;
padding: .5rem 1rem;
position: relative;
top: 0;
left: 0;
width: 178px;
height: 40px;
outline: none;
border: 1px solid #CCCCCC;
border-radius: 6px;
transition: all .5s;
}
input[type="search"]:focus {
width: 300px;
top: 0;
right: 100%;
}
<div style="text-align:right;">
<input type="search" id="search" />
</div>

Answer 2

Position the input absolutely and set the right property to zero:
position:absolute;
right:0;
That forces the expansion to the left when focused.
jsFiddle example

Answer 3

Make your containers offset parents using position: relative.
#header, #search {
width: 100%;
position: relative;
}
Then position your input using position: absolute and place it using right.
#header #search input {
position: absolute;
right: 0px;
background: #FFF;
padding: 1px 1px 1px 5px;
width: 178px;
height: 21px;
border: 1px solid #CCCCCC;
border-radius: 6px;
-webkit-transition: all .5s;
-moz-transition: all .5s;
transition: all .5s;
}
#header #search input:focus {
background: #FFF;
padding: 1px 1px 1px 5px;
width: 300px;
height: 21px;
border: 1px solid #CCCCCC;
Your animation will now stretch to the left.